The short version: SA1 is the form you use to register for Self Assessment with HMRC. If you have untaxed income and need to file a tax return, this is where you start.
When do you need to register?
If you’re self employed and earning above the trading allowance, if you have rental income, if you want to claim certain tax reliefs, or if you earned above certain thresholds. You need to register by 5th October following the end of the tax year you’re registering for.
How do you register?
You can do it online through HMRC’s website (easier and faster) or download the SA1 form and post it. Online is recommended unless you have a specific reason to use paper.
What happens next?
HMRC will send you a Unique Taxpayer Reference (UTR) number. You’ll need this to file your tax return. Keep it safe because you’ll use it every year.
Need to register for Self Assessment? We can help you get set up properly.
